LightSquared's plan to build a nationwide 4G network was hit by what seemed like a death blow in February, when the Federal Communications Commission revoked its tentative approval because the network would interfere with GPS devices. But LightSquared has influential friends, and lawmakers were eager to blame the FCC, even if they didn't really understand the technical reasons that caused LightSquared's proposal to fail. Spectrum swaps with federal users to bail out the company have also been proposed.

LightSquared came up with its own proposal on Friday (PDF), which involves sharing 5MHz of spectrum with the federal government in a band partially used for weather balloons. It also involves abandoning its most controversial piece of spectrum, the one just below the GPS signals. But LightSquared still wants to build on the lower 10MHz of its spectrum, even though the FCC has already rejected it as unsuitable because millions of existing GPS devices can't filter out neighboring signals. To compensate, LightSquared would lower the power levels in this portion of spectrum to 52dBm per sector EIRP, down from the previously planned power level of 62dBm, which was found to interfere with GPS.

Specifically, LightSquared is proposing to relinquish any claim on the 10MHz (1545-1555 MHz) closest to the GPS band. It is simultaneously asking for rule changes (PDF) that would permit its "eventual robust commercial use of that lower 10MHz of spectrum," a downlink band at 1526-1536 MHz.

This isn't much of a concession. LightSquared already agreed to temporarily give up on deploying in the upper 10MHz. But that wasn't sufficient. "Based on the testing and analyses conducted to date, as well as numerous discussions with LightSquared, it is clear that LightSquared's proposed implementation plans, including operations in the lower 10MHz, would impact both general/personal navigation and certified aviation GPS receivers," the National Telecommunications and Information Administration (NTIA) told the FCC in February. That information led to the withdrawal of LightSquared's conditional approval to deploy terrestrial broadband services.

LightSquared's approval from the previous year had been conditioned on preventing interference with GPS devices. The NTIA did find that LightSquared could prevent interference with GPS by adjusting power levels, antenna height, and antenna angles, but LightSquared rejected this as impractical. Such modifications would prevent the proposed network from hitting appropriate service levels without an investment of billions to build more base stations, which would in any case cause more interference with GPS receivers.

LightSquared "volunteers" to delay use of spectrum it can't use anyway

LightSquared does seem resigned to at least some further delay in deploying on the lower 10MHz, as it says it would "voluntarily" not deploy on that lower 10MHz while the FCC conducts the potential rulemaking proceeding. Since the FCC has already explicitly told LightSquared it cannot deploy on this chunk of spectrum, the use of the word "voluntarily" is an interesting one.

LightSquared hopes its concessions, including the lower power level and some geographic restrictions, will allow limited use of the lower 10MHz until it becomes viable to proceed with "robust terrestrial use of that spectrum." But robust deployment could well require major changes to GPS receiver standards, and replacement of millions of existing GPS devices already deployed for personal and public safety use. Even if a government plan to overhaul GPS standards is devised, it would take many years to implement because of the huge GPS install base.

The new part of LightSquared's proposal involves deploying terrestrial services on 1670-1675 MHz, which LightSquared already has authority to use nationwide, and on 1675-1680 MHz, which LightSquared wants to share with federal government users. This would create a contiguous 10MHz of spectrum for downlink to get the network started, while LightSquared would use its uplink bands of 1627.5-1637.5 MHz and 1646.7-1656.7 MHz.

The 1675-1680 spectrum is "used for federal purposes including National Oceanographic and Atmospheric Administration weather balloons," the IDG News Service reports. The FCC is moving ahead with spectrum sharing—but getting spectrum from the government is not easy, and the federal spectrum LightSquared wants isn't part of the 1,000MHz the government is targeting for sharing.

"I suppose if they avoid using bands that cause problems for GPS and are able to figure out some way of sharing government spectrum, then the proposal is technically feasible," wireless researcher Peter Rysavy told Ars via e-mail. "However, making sharing work is potentially very complicated, so it could be a long-term process to figure out the mechanics. Beyond technology, the politics of getting the spectrum swapped could also be very challenging."

The lower 10MHz did cause problems for GPS in government testing, as we noted earlier, and GPS makers have opposed LightSquared's plans.

In a response to LightSquared's latest proposal, GPS maker Trimble said it "supports the initiation of a rulemaking proceeding to consider the appropriate long term use of the mobile satellite spectrum adjacent to GPS," but wants to avoid paying lots of money to overhaul GPS devices.

"The issue is not merely whether there are ‘technology solutions’ to interference issues, but whether or not those solutions can be implemented at reasonable cost and without substantially hindering future innovation in location-based products and services," Trimble VP and general counsel Jim Kirkland said in a statement e-mailed to Ars. "Moreover, consistent with established FCC policy, any such costs must be borne by the new spectrum use, not US businesses and consumers who rely on GPS." Kirkland did not say whether LightSquared's newly proposed power levels are low enough to prevent interference.

LightSquared's friends in Congress want the FCC to get its network back on track immediately. US Rep. Cliff Stearns (R-FL) recently demanded a solution from FCC officials, but FCC Chief of Engineering and Technology Julius Knapp said LightSquared's fate is subject to an open proceeding, and it's too early to endorse any one proposal.

Congressional Republicans have been split on LightSquared, a story in The Hill notes, with some blasting President Obama for helping LightSquared too much, and others accusing Obama's administration of deliberately torpedoing LightSquared's proposal.

Why should Lightsquared be able to recover anything? They tried to gladhand and schmooze their way to a cheap nationwide data network and it blew up in their faces because older GPS devices didn't care about Beltway dinner parties.

Congress should tell Lightsquared to go bid for spectrum applicable to the usage like everyone else. QED.

This is where I get frustrated in government and business. How many of my tax dollars are being wasted here because neither side understands basic fucking physics? I know this has been discussed on these technical forums ad nauseam, but the short of it is you can't broadcast terrestrial strength signals next to a satellite band and expect a useful signal to noise ratio anymore. Won't work, can't work, and no matter how you reframe the damn issue, it's not feasible without re-engineering every GPS receiver out there. Some things you can't talk into working no matter how many angles one try's to take. Sisyphean article reference indeed.

but the short of it is you can't broadcast terrestrial strength signals next to a satellite band and expect a useful signal to noise ratio anymore.

Oh, come on. Surely you have a magic filter design that can separate a 62dBm signal transmitter a few hundred meters away from a -130dBm signal received from orbit!

They'll even be nice and back down to 52dBm for you.

Just, like, whip up a magic filter and call it good!

Donkey Hotay wrote:

Congress should tell Lightsquared to go bid for spectrum applicable to the usage like everyone else. QED.

Yup. They tried to repurpose spectrum in a manner that physics doesn't allow, and are now trying to worm their way out of that by proposing "trades" and "swaps" and "sharing," helped by the congresscritters in their pocket.

Total side question -- Why are 5Mhz reserved for Weather Balloons? This seems like a huge amount of spectrum for something that requires very little (or seriously, none? Can't they simply use cellular or satcom uplinks in modern times?).

Total side question -- Why are 5Mhz reserved for Weather Balloons? This seems like a huge amount of spectrum for something that requires very little (or seriously, none? Can't they simply use cellular or satcom uplinks in modern times?).

I don't think the entire 5MHz is for weather balloons. That's why it says "partially" used for weather balloons.

This again? OK, time for another plan guys....clearly using physics, math, reason, and logic isn't an effective way to win an argument.

So, let us consider that (at least, as far as I know) the military uses the same GPS that will be totally screwed by this proposal. So, let us rally under the flag of "defend the homeland!" and "save the children!" and work from that angle. Surely the DOD doesn't want to retrofit/replace all of their GPS receivers too?

In fact, if we claim Lightsquared to be an Al-Qaeda plot, we can chalk up another "victory" in the war-on-terror at the same time!

Total side question -- Why are 5Mhz reserved for Weather Balloons? This seems like a huge amount of spectrum for something that requires very little (or seriously, none? Can't they simply use cellular or satcom uplinks in modern times?).

I don't think the entire 5MHz is for weather balloons. That's why it says "partially" used for weather balloons.

Keep in mind that the 5mhz has probably been dedicated to weather balloons for decades(I couldn't find a reference off hand). I'm assuming back when they got it we were much less adept at transmitting data and didn't have huge cell and satcom installations already present..

Question: why is LightSquared such an emotional trigger here on ARS? Sure, it's an example of how corrupt American politics are, but there are plenty of those. There's some junk science, but that's also not uncommon.

What is it about this topic that brings out the level of emotion and anger usually reserved for climate change or internet surveillance?

Someone forgot to tell Lightsquared that a 10dbm reduction isn't squat and still would fuck over GPS. Oh wait... yep they were told that already during previous testing. It's the zombie that just won't die. But hey, lets go borrow some weather balloon frequency instead, cause who ever would need to use those.

Keep on it LightSquared! You are right on. We need a competitor in the US that can provide low cost mobile data. We are at the mercy of a duopoly...VZ and ATT. The rest of the mobile guys are too far behind to be make a difference.As to the interference....I call B.S. on the NTIA testing. The LS spectrum is 23 MHz away from the GPS band. You think 5MHz on weather balloons is bad....how about a 23 MHZ guardband? And Kirkland from Trimble built the trillion $$ business on this free spectrum...Talk about leaches.NTIA tests at this new lower power show that the devices pass. There is no need for a magic filter. Plenty of people continue to post this fiction on Ars. It is not true.

So they had this plan, schmoozed the politicians to get it approved, and apparently spent much time, energy, and cash doing it all. Except they hadn't accounted for the laws of the natural world. Which they now blame the FCC for and demand 'a fix' to their problem.

Keep saying no, guys. Tell them where they can put their back room deals.

Total side question -- Why are 5Mhz reserved for Weather Balloons? This seems like a huge amount of spectrum for something that requires very little (or seriously, none? Can't they simply use cellular or satcom uplinks in modern times?).

I don't think the entire 5MHz is for weather balloons. That's why it says "partially" used for weather balloons.

It looks like the weather balloon band is from 1675-1685mhz, so this would cut out half of the band, however it also looks like the transmitter used are 300 milliwatts or less, which means if Lightsquared transmits at significant power next to that, it would make it difficult to receive weather balloon transmissions as well.

By the way, I wanted to say this was a much better article then the last one. Thank you.

Keep on it LightSquared! You are right on. We need a competitor in the US that can provide low cost mobile data. We are at the mercy of a duopoly...VZ and ATT. The rest of the mobile guys are too far behind to be make a difference.As to the interference....I call B.S. on the NTIA testing. The LS spectrum is 23 MHz away from the GPS band. You think 5MHz on weather balloons is bad....how about a 23 MHZ guardband? And Kirkland from Trimble built the trillion $$ business on this free spectrum...Talk about leaches.NTIA tests at this new lower power show that the devices pass. There is no need for a magic filter. Plenty of people continue to post this fiction on Ars. It is not true.

And you keep showing up to spout info that is wrong on so many levels, leaches my ass.... please, just stop.

Total side question -- Why are 5Mhz reserved for Weather Balloons? This seems like a huge amount of spectrum for something that requires very little (or seriously, none? Can't they simply use cellular or satcom uplinks in modern times?).

Don't you know? Weather Balloons is totally governmentspeak for UFO's. That 5Mhz is what the Government uses to communicate with the aliens. Jeez, if you are going to come to a tech site, at least know the Jargon.

Keep on it LightSquared! You are right on. We need a competitor in the US that can provide low cost mobile data. We are at the mercy of a duopoly...VZ and ATT. The rest of the mobile guys are too far behind to be make a difference.As to the interference....I call B.S. on the NTIA testing. The LS spectrum is 23 MHz away from the GPS band. You think 5MHz on weather balloons is bad....how about a 23 MHZ guardband? And Kirkland from Trimble built the trillion $$ business on this free spectrum...Talk about leaches.NTIA tests at this new lower power show that the devices pass. There is no need for a magic filter. Plenty of people continue to post this fiction on Ars. It is not true.

Question: why is LightSquared such an emotional trigger here on ARS? Sure, it's an example of how corrupt American politics are, but there are plenty of those. There's some junk science, but that's also not uncommon.

What is it about this topic that brings out the level of emotion and anger usually reserved for climate change or internet surveillance?

Initially, at least, a bunch of kids and/or electromagnetic physics-impaired adults would show up and cheer for LS and against "evil" government preventing them from deploying the spectrum (I suspect they were mostly RON PAUL fanatics who hate government with a fervor). That seems to have gone away mostly once the reality of the situation and more understanding about how signals next to each other work.

This proposal is OK, testing needs to be done of course, and independently verified that it still wont harm GPS devices. If weather balloons can co-exist with LS (which is what LS is proposing, federal spectrum sharing, not an outright takeover), then I'd be OK with it.

What I'd really like to see is Charlie Ergen get his hands on this spectrum and use it to augment the 40MHz terrestrial cell network he is planning on building with his 2.0/2.2GHz spectrum. They could use the LS spectrum for satellite-ground for areas without terrestrial coverage, and have a fast nationwide LTE network. But I doubt Falcone wants that to happen since it would destroy the value of LS.

Keep on it LightSquared! You are right on. We need a competitor in the US that can provide low cost mobile data. We are at the mercy of a duopoly...VZ and ATT. The rest of the mobile guys are too far behind to be make a difference.As to the interference....I call B.S. on the NTIA testing. The LS spectrum is 23 MHz away from the GPS band. You think 5MHz on weather balloons is bad....how about a 23 MHZ guardband? And Kirkland from Trimble built the trillion $$ business on this free spectrum...Talk about leaches.NTIA tests at this new lower power show that the devices pass. There is no need for a magic filter. Plenty of people continue to post this fiction on Ars. It is not true.

Not sure the angle behind this poster. Started posting in Febuary of '12 on this topic, and only this topic. 63 pro lightsquared posts, nothing else during the intervening time. Not sure if troll, shill, astroturfer, uninformed, or some combination of the four. Just my opinion.

Maybe they should just buy some of the TV spectrum that's going to be auctioned off soon in the TV band spectrum repacking, since Congress decided that a drop in the Treasury is better than a bucket in the economy?

It's the perfect frequency band for 4G, and it's being allocated for terrestrial mobile broadband usage...

oh wait, that means they'd have to pay *market rates* for licensed frequencies and use as the spectrum is allocated, costing them billions more than the junk band they bought!

We can't have them competing on a level field with AT&T and Verizon now, can we?

While I really applaud the concept of a nationwide wholesale 4G network, the way these guys are going about it is just dirty pool at its' finest.

Wouldn't the easiest solution be for the FCC to refund any money paid for the spectrum, and tell LightSquared to bid on new spectrum when it becomes available for the purposes they require?

LS didn't bid on this spectrum in the first place. Its like if a neighborhood strip mall went out of business, and I came in and wanted to demolish it and build a Casino. You bet your ass the neighbors would be up in arms. The local government cant "refund" anything since it wasn't the one selling the property in the first place.

Total side question -- Why are 5Mhz reserved for Weather Balloons? This seems like a huge amount of spectrum for something that requires very little (or seriously, none? Can't they simply use cellular or satcom uplinks in modern times?).

There is the same "roughly equidistant from a lot of cells" problem that motivates banning use of cell phones from in-flight aircraft. ALL types of aircraft, balloons included.

Even without that issue, cellular would be tough because cell towers don't try to cover the sky. Since directional antennas aren't perfectly directional, they do have "lobes" that reach above the horizontal, but these aren't to be counted upon for communications.

Yah know, it took this article for me to realize that even if LightSquared somehow managed to get this working, I wouldn't use their damn service even if it was $4.99 a month for unlimited LTE type speeds. Their behavior on a corporate level has irritated me to the point that I will not support them EVER. I try not to support companies who act like idiots to begin with (Physics beeches! Learn it!!) and then go running to the gov reps and go NOT FAIR!!

I also look down on companies that actively deploy astroturfers to try and sway public opinion. While I don't have proof of LightSquared doing this, I've been on too many various discussion boards where the stink of astroturfing is strong.

Total side question -- Why are 5Mhz reserved for Weather Balloons? This seems like a huge amount of spectrum for something that requires very little (or seriously, none? Can't they simply use cellular or satcom uplinks in modern times?).

I don't think the entire 5MHz is for weather balloons. That's why it says "partially" used for weather balloons.

It looks like the weather balloon band is from 1675-1685mhz, so this would cut out half of the band, however it also looks like the transmitter used are 300 milliwatts or less, which means if Lightsquared transmits at significant power next to that, it would make it difficult to receive weather balloon transmissions as well.

By the way, I wanted to say this was a much better article then the last one. Thank you.

Which comes back to my original question -- Why do weather balloons need any spectrum allocation?

This is where I get frustrated in government and business. How many of my tax dollars are being wasted here because neither side understands basic fucking physics? I know this has been discussed on these technical forums ad nauseam, but the short of it is you can't broadcast terrestrial strength signals next to a satellite band and expect a useful signal to noise ratio anymore. Won't work, can't work, and no matter how you reframe the damn issue, it's not feasible without re-engineering every GPS receiver out there. Some things you can't talk into working no matter how many angles one try's to take. Sisyphean article reference indeed.

But, typically in Congress, being told "it's impossible" merely means that the proposer hasn't made it worth the other person's while to endorse the project. So, Rep. Stearns merely views this as an issue of the same ol' political brinkmanship, rather than an actual physics problem (not that he'd know anything about an actual physics problem).

I know a good way to demonstrate the problem to Rep. Stearns - place Rep. Stearns in a plane with no windows, guided by GPS info only. Then, turn on the Lightsquared towers. Let's see if, assuming he lands safely again, he understands the problem that the military (and others) have with Lightsquared's set up.

Wouldn't the easiest solution be for the FCC to refund any money paid for the spectrum, and tell LightSquared to bid on new spectrum when it becomes available for the purposes they require?

I say the FCC should offer to buy it back for what it's worth, or a maximum of 80% of the price LS paid. That would be fair since it is now a slightly used spectrum instead of brand new.

Really though, LS made a dumb move while thinking they were being crafty. It happens, but I don't think being rewarded with a 'it's ok, we'll refund your money, better luck next time' response is right.

Frankly, the whole thing has been a scam from the beginning. The FCC licensed that spectrum for a specific use. If the use is going to be changed, then the windfall profit should go to the owner of the spectrum (the American people) and not some clever company with good connections in Congress.

What the FCC is doing with TV makes a whole lot more sense. Buy back a range of spectrum from existing license-holders, then auction it off as cellular spectrum, reaping billions for the treasury.

Which comes back to my original question -- Why do weather balloons need any spectrum allocation?

They can't communicate to cell towers as the cell towers are not aimed in the appropriate direction, it is used strictly as a one way communication, from balloon to ground and it would be incredibly difficult to transmit reliably to a sat in orbit with only a 300 milliwatt transmitter and a non steerable antenna. As the site I link stated they are used for a wide number of weather observations, and are used daily in weather modeling. Here is a link to a Wiki page for info as well. http://en.wikipedia.org/wiki/Radiosonde

Personally that sounds like a fairly useful service to me. Is there a better way to do it, maybe, but i'm not sure Lightsquared really cares.

Which comes back to my original question -- Why do weather balloons need any spectrum allocation?

Because they're cheap and essentially disposable. Keeping the frequencies where they are allow the balloon to transmit in the clear to their respective stations with a lat-lon, temperature, pressure, and wind speed. The entire package is less then $100, but each launch site is only able to launch 2 per day due to the NWS radiosonde allocation.

Would you rather they launch a $2 radio transmitter every time or a $10 cellular data chip? That has to transmit to the surface from 15-20 km in the air? There's still no better data collection vector then a radiosonde, and the cheapest way to improve forecast accuracy would be to double or triple the amount of sondes launched per day.

Which comes back to my original question -- Why do weather balloons need any spectrum allocation?

Weather balloons transmit results back to the ground using cheap, mass-produced, very-low-power FM transmitters. Because of the long distances they can travel, the spectrum has to be clear or the signals would get lost quickly. The instrumentation is completely disposable, so has to be cheap, cheap, cheap to produce (they crash to the ground when the balloon finally pops). They fly too high for cellular signals, and satellite communication would be expensive.